Prior art airsprings had lower retainer assemblies where the combination studs were imbedded into the plastic lower retainer body during injection molding (see FIG. 1). Due to variations in shrinkage between the plastic body and the metal stud, air leaks occurred at the plastic/metal interface.
The present invention has solved this problem by molding a retainer body, having a seat, first then press fitting a combination stud, having a head, into the retainer body with an o-ring in between.